Mobile apparatus, and control method thereof, control program and supervisory system therefor

ABSTRACT

A mobile apparatus or the like capable of moving or acting by avoiding contact with an object, such as a person, while reducing the possibility of inducing a change of the behavior of the object. It is determined whether or not there is a first spatial element Q 1  that satisfies a contact condition that there is a possibility of contact with a reference spatial element Q 0  on a discriminant plane. The reference spatial element Q 0  and the first spatial element Q 1  represent current images of a robot  1  and an object x, respectively. When it is determined that there is a first spatial element Q 1  that satisfies the contact condition on the discriminant plane, a route that allows the reference spatial element Q 0  to move by avoiding contact with a second spatial element Q 2  is set as a new “first action plan element” on the discriminant plane.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus capable of autonomouslymoving according to a movement plan, for example.

2. Description of the Related Art

As the functionality of robots is enhanced, robots have had moreopportunities to carry a burden or guide a person to a destination, forexample, and thus, there is an increasing demand for a technique thatallows robots to move by avoiding contact with people around them. Therehas been proposed a technique that allows a robot to move by avoidingcontact with a plurality of objects (obstacles) around it by taking intoaccount the movement velocities of the objects (see “Planning andnavigation by a mobile robot in the presence of multiple movingobstacles and their velocities”, Journal of the Robotics Society ofJapan, Vol. 12, No. 7, pp. 1029-1037, 1994). According to thistechnique, in order to plan an optimum path for reaching a destinationwhile avoiding contact between a robot and objects, prediction of themovement of each object and planning of a path that involves no contactbetween the robot and the objects based on the prediction are repeatedin short cycles.

SUMMARY OF THE INVENTION

However, if a robot immediately changes the behavior in response to achange of the behavior of a person around it, such as a change of themovement velocity (including the direction) of the person, the change ofthe behavior of the robot can induce a change of the behavior of theperson or another person, thereby increasing the possibility of contactbetween the robot and the people. For example, if the robot immediatelymoves to the left in response to a person facing the robot moving towardthe right of the robot, the person or another person can change themovement direction in response to this to thereby increase thepossibility of contact between them. In this case, it is difficult forthe robot and the people around it to move in harmony.

Thus, an object of the present invention is to provide a mobileapparatus or the like that is capable of moving or acting by avoidingcontact with an object, such as a person, while suppressing thepossibility that the movement or action of the mobile apparatus inducesa change of the behavior of the object.

According to a first aspect of the present invention, there is provideda mobile apparatus that has a control system and autonomously movesaccording to a first action plan element under the control of thecontrol system, in which the control system comprises: a firstprocessing section that recognizes a current image of the mobileapparatus, a current image of an object, and an intermittent orcontinuous future image of the object, which is determined according tothe behavior of the object and has a larger size than the current imagethereof, as a reference spatial element, a first spatial element and asecond spatial element having a larger size than the first spatialelement on a discriminant plane, respectively; a second processingsection that determines, based on the result of the recognition by thefirst processing section, whether or not there is a first spatialelement that satisfies a contact condition that there is a possibilityof contact with the reference spatial element on the discriminant plane;and a third processing section that sets a route that allows thereference spatial element to avoid contact with the second spatialelement on the discriminant plane as the first action plan element basedon the result of the recognition by the first processing section, whenthe second processing section determines that there is a first spatialelement that satisfies the contact condition on the discriminant plane.

The mobile apparatus according to the first aspect of the presentinvention recognizes a current image of the mobile apparatus, a currentimage of an object, and an intermittent or continuous future image ofthe object, which is determined according to the behavior of the object,as a “reference spatial element”, a “first spatial element” and a“second spatial element” on a discriminant plane, respectively. Sincethe intermittent or continuous future image of the object has a largersize than the current image of the object, the second spatial element isrecognized on the discriminant plane as a spatial element having alarger size than the first spatial element. In other words, the firstspatial element is recognized on the discriminant plane as a spatialelement having a smaller size than the second spatial element. Here, the“discriminant plane” is a flat surface or a curved surface defined totwo-dimensionally recognize the position, the shape and the size of themobile apparatus or the like in the real space. “A discriminant plane”means “one discriminant plane” or “each discriminant plane of a group ofdiscriminant planes”. A “spatial element” on the discriminant plane isdefined as a point, a segment, a region, a closed curve (a contour of aregion) or the like on the discriminant plane. If an object is attachedto the mobile apparatus and moves together with the mobile apparatus,for example, the mobile apparatus and the object are collectivelyrecognized as the first spatial element on each discriminant plane.

Furthermore, it is determined whether or not there is a first spatialelement that satisfies a “contact condition” that there is a possibilityof contact with the reference spatial element on the discriminant plane.When it is determined that there is a first spatial element thatsatisfies the contact condition, a route that allows the referencespatial element to move by avoiding contact with the second spatialelement on the discriminant plane is set as a “first action planelement”. Specifically, in a situation in which the mobile apparatus ishighly required to avoid contact with an object, a route as the firstaction plan element can be newly set based on the behavior of the mobileapparatus and the object recognized as the reference spatial element andthe first spatial element on the discriminant plane, respectively, whichis defined by the position, the velocity, the acceleration and the likethereof, and the contour characteristics thereof, such as the shape andthe size. The mobile apparatus can continue moving while avoidingcontact with the object by following the new route as the first actionplan element.

As described above, the first spatial element is recognized as a spatialelement having a smaller size than the second spatial element on thediscriminant plane, and the presence of a first spatial element thatsatisfies the contact condition is a requirement for setting a new firstaction plan element. In other words, to change the route, it is requiredthat a first spatial element, which has a smaller size than the secondspatial element, rather than a second spatial element, satisfies thecontact condition. Therefore, compared with a case where it is requiredto change the first action plan element that there is a spatial elementlarger than the first spatial element, such as the second spatialelement, that can come into contact with the reference spatial element,the frequency of change of the route as the first action plan elementand, therefore, the frequency of change of the movement direction arereduced. Thus, the possibility that a change of the behavior of themobile apparatus induces a change of the behavior of the object can bereduced.

Furthermore, if each spatial element is recognized on each of aplurality of discriminant planes, and it is required to change the firstaction plan element that there is a first spatial element that can comeinto contact with the reference spatial element on any of the pluralityof discriminant planes, the route can be changed by taking into accountthe three-dimensional shape of the mobile apparatus and the object.Specifically, in general, the mobile apparatus and the object each havethree-dimensional contour characteristics in which the longitudinal sizeand the lateral size vary with the position, such as the height from thefloor surface. Therefore, the shapes and the sizes of the mobileapparatus and the object at different positions can be reflected in theshape and the size (including the relative size of one spatial elementwith respect to the other spatial element) of the reference spatialelement and the first spatial element recognized on the respectivediscriminant planes. Therefore, when preventing the mobile apparatusrecognized as the reference spatial element from coming into contactwith the object recognized as the first spatial element is necessary orappropriate, the route as the first action plan element can be changedin view of the three-dimensional contour characteristics and thebehavior, such as the position and the velocity, of the mobile apparatusand the object.

Furthermore, as described above, the second spatial element isrecognized as a spatial element having a larger size than the firstspatial element on the discriminant plane, and a new route as the firstaction plan element is set to avoid contact between the referencespatial element and the second spatial element. Therefore, compared witha case where a route is set that allows the reference spatial element toavoid contact with a spatial element having a smaller size than thesecond spatial element, such as the first spatial element, appropriateroute and action plan that allow the mobile apparatus to avoid contactwith the object with reliability can be set.

Therefore, the mobile apparatus can move by avoiding contact with theobject while reducing the possibility that the movement of the mobileapparatus induces a change of the behavior of the object, such as aperson.

In this specification, the expression that a constituent spatial element“recognizes” information means that the constituent spatial elementperforms any processing for preparing information for a requiredinformation processing, such as reading information from a storagedevice, such as a memory, retrieving information from a database,receiving information using a communication feature, performingmeasurement, estimation, calculation, setting, prediction or the like ofrequired information from basic information retrieved or otherwiseobtained, and storing information measured or otherwise obtained in amemory.

According to a second aspect of the present invention, in the mobileapparatus according to the first aspect of the present invention, thefirst processing section recognizes the behavior of the object by someor all of the position, the velocity and the acceleration of the firstspatial element on the discriminant plane and recognizes the firstspatial element intermittently or continuously extended according to theresult of the recognition so that the second spatial element does notinclude the reference spatial element, as the second spatial element.

According to the second aspect of the present invention, the size of thesecond spatial element on the discriminant plane is determined accordingto at least one of the position, the velocity and the acceleration ofthe first spatial element on the discriminant plane determined accordingto the behavior of the object. Therefore, the mobile apparatus can moveor act so that the mobile apparatus does not come into contact with asuperimposed future image of the object predicted based on the positionor the like of the object.

According to a third aspect of the present invention, in the mobileapparatus according to the second aspect of the present invention, thefirst processing section recognizes the behavior of the object by thevelocity of the first spatial element and the relative position and therelative velocity of the first spatial element with respect to thereference spatial element on the discriminant plane and recognizes thefirst spatial element intermittently or continuously extended accordingto the result of the recognition as the second spatial element.

According to the third aspect of the present invention, the size of thesecond spatial element on the discriminant plane is determined accordingto the velocity of the first spatial element and the relative positionand the relative velocity of the first spatial element with respect tothe reference spatial element on the discriminant plane determinedaccording to the behavior of the object. Therefore, the mobile apparatuscan move or act so that the mobile apparatus does not come into contactwith a superimposed future image of the object predicted based on thevelocity of the object, and the relative position and the relativevelocity of the object with respect to the mobile apparatus.

According to a fourth aspect of the present invention, in the mobileapparatus according to the first aspect of the present invention, thefirst processing section recognizes a region determined according to thecontour characteristics of the object extended according to the contourcharacteristics of the mobile apparatus as the first spatial element onthe discriminant plane.

According to the fourth aspect of the present invention, the contourcharacteristics of the mobile apparatus and the object can becollectively reflected in the contour characteristics of the firstspatial element on the discriminant plane. Therefore, the precision ofthe determination of whether there is a possibility of contact betweenthe reference spatial element and a first spatial element can beimproved or maintained while simplifying the handling of the referencespatial element on the discriminant plane and therefore thedetermination process, for example.

According to a fifth aspect of the present invention, in the mobileapparatus according to the fourth aspect of the present invention, thefirst processing section recognizes a Minkowski sum of two regionsdetermined according to the contour characteristics of the mobileapparatus and the object as the first spatial element on thediscriminant plane.

According to the fifth aspect of the present invention, the contourcharacteristics of the mobile apparatus and the object can becollectively reflected in the contour characteristics of the firstspatial element, which is a Minkowski sum, on the discriminant plane.Therefore, the precision of the determination of whether there is apossibility of contact between the reference spatial element and a firstspatial element can be improved or maintained while simplifying thehandling of the reference spatial element as a dot or a small region onthe discriminant plane and therefore the determination process, forexample.

According to a sixth aspect of the present invention, in the mobileapparatus according to the first aspect of the present invention, thesecond processing section determines, based on the result of therecognition by the first processing section, whether or not there is thefirst spatial element that satisfies a first contact condition, as thecontact condition, concerning a movement cost of the reference spatialelement on the discriminant plane.

According to the sixth aspect of the present invention, when it isdetermined that there is a first spatial element that satisfies thefirst contact condition concerning the movement cost of the referencespatial element on the discriminant plane, it is determined that thereis a possibility of contact between the reference spatial element and afirst spatial element on the discriminant plane. The “movement cost” isevaluated to be higher as the time required for the movement is longer,or the distance from the mobile apparatus is longer, for example. Asdescribed above, when it is determined that there is a first spatialelement that can come into contact with the reference spatial element,the first action plan element is changed. Therefore, the mobileapparatus can move by avoiding contact with the object while reducingthe frequency of change of the behavior of the mobile apparatus thatinduces a change of the behavior of the object, such as a person. For afirst spatial element corresponding to an object for which the movementcost of the mobile apparatus is high, and the possibility of contactwith the mobile apparatus is currently low, the processing of changingthe action plan element or the like based on the result of determinationof the possibility of contact between the first spatial element and thereference spatial element is omitted, and the information processingload is reduced accordingly.

According to a seventh aspect of the present invention, in the mobileapparatus according to the sixth aspect of the present invention, thesecond processing section determines whether or not there is the firstspatial element that satisfies the first contact condition that themovement cost falls within a prescribed range or is at a predeterminedrank or lower.

According to the seventh aspect of the present invention, only when themovement cost of the mobile apparatus to the object is low, and it isdetermined that the two can come into contact with each other, actionplan elements including the first action plan element can be changed inorder to avoid contact between the mobile apparatus and the object.Therefore, the mobile apparatus can move by avoiding contact with theobject while reducing the frequency of change of the behavior of themobile apparatus that induces a change of the behavior of the object,such as a person.

According to an eighth aspect of the present invention, in the mobileapparatus according to the seventh aspect of the present invention, thesecond processing section determines whether or not there is the firstspatial element that satisfies the first contact condition that themovement cost falls within the prescribed range having a positive lowerlimit.

According to the eighth aspect of the present invention, the action planelement is not changed when the object is located near the mobileapparatus, and therefore, a change of the behavior of the mobileapparatus can induce an unexpected change of the behavior of the objectto thereby increase the possibility of contact therebetween.

According to a ninth aspect of the present invention, in the mobileapparatus according to the first aspect of the present invention, thesecond processing section determines whether or not there is the firstspatial element that satisfies a second contact condition, as thecontact condition, concerning the positional relationship between thefirst spatial element and the route as the first action plan element.

According to the ninth aspect of the present invention, only when thereis a first spatial element that satisfies the “second contact condition”concerning the positional relationship with the route of the referencespatial element on the discriminant plane, it can be determined thatthere is a possibility of contact between the reference spatial elementand the first spatial element on the discriminant plane. As describedabove, when it is determined that there is a first spatial element thatcan come into contact with the reference spatial element, the firstaction plan element is changed. Therefore, the mobile apparatus can moveby avoiding contact with the object while reducing the frequency ofchange of the behavior of the mobile apparatus that induces a change ofthe behavior of the object, such as a person. In addition, when it isdetermined, from the positional relationship between the route of thereference spatial element and the first spatial element, that there isno possibility of contact between the mobile apparatus and all theobjects around the mobile apparatus, the processing of changing theaction plan element based on the result of determination of thepossibility of contact between the reference spatial element and thefirst spatial element is omitted, and the information processing load isreduced accordingly.

According to a tenth aspect of the present invention, in the mobileapparatus according to the ninth aspect of the present invention, thesecond processing section determines whether or not there is the firstspatial element that satisfies the second contact condition that thereis an intersection or contact between the first spatial element and thereference spatial element moving along the route as the first actionplan element.

According to the tenth aspect of the present invention, only when it isdetermined that, if the mobile apparatus moves along the route as thefirst action plan element, the possibility of contact with the object ishigh, the action plan element can be changed to avoid contact with theobject. Therefore, the mobile apparatus can move by avoiding contactwith the object while reducing the frequency of change of the behaviorof the mobile apparatus that induces a change of the behavior of theobject, such as a person.

According to an eleventh aspect of the present invention, in the mobileapparatus according to the first aspect of the present invention, thethird processing section sets, as the first action plan element, acondition that the rate of change of either or both of the direction andthe magnitude of the velocity of the mobile apparatus is equal to orlower than a threshold value.

According to the eleventh aspect of the present invention, an excessivechange of the velocity of the mobile apparatus caused by a change of thefirst action plan element and a change of the behavior of the mobileapparatus caused thereby can be suppressed. Therefore, the possibilitycan be avoided that a change of the behavior of the mobile apparatusinduces an unexpected change of the behavior of the object to therebyincrease the possibility of contact between the mobile apparatus and theobject. In addition, the possibility can be avoided that the mobileapparatus is forced to change the velocity and, therefore, the behaviorbeyond the capacity thereof.

According to a twelfth aspect of the present invention, in the mobileapparatus according to the first aspect of the present invention, thethird processing section sets, as the first action plan element, acondition that a higher priority is given to changing the magnitude ofthe velocity of the mobile apparatus than changing the directionthereof.

According to the twelfth aspect of the present invention, taking intoaccount the fact that a change of the direction of the velocity(movement direction) of the mobile apparatus is more likely to induce achange of the behavior of the object, a priority is given to changingthe magnitude of the velocity (speed) of the mobile apparatus thanchanging the direction thereof. Therefore, the frequency of change ofthe behavior of the mobile apparatus that induces a change of thebehavior of the object is reduced.

According to a thirteenth aspect of the present invention, in the mobileapparatus according to the first aspect of the present invention, thecontrol system controls the operation of an on-board device installed inthe mobile apparatus according to a second action plan element, and thethird processing section prepares an announcement of the movementdirection of the mobile apparatus as the second action plan element.

According to the thirteenth aspect of the present invention, themovement direction can be announced to the object, such as a person, byan operation of an on-board device according to the second action planelement at an appropriate timing, such as immediately before changingthe movement direction. Therefore, a behavior of the object, such asturning, that reduces the possibility of contact with the mobileapparatus can be induced, and the possibility of contact between themobile apparatus and the object can be reduced.

According to a fourteenth aspect of the present invention, in the mobileapparatus according to the thirteenth aspect of the present invention,the mobile apparatus has a driving device for driving a movable partcorresponding to a part of a human body as the on-board device, and thethird processing section prepares an announcement of the movementdirection as the second action plan element by a movement of the drivingdevice.

According to the fourteenth aspect of the present invention, the personrecognized as the object can naturally and clearly recognize themovement direction of the mobile apparatus from actions of movable partscorresponding to parts of a human body, such as a head, an arm, a legand a trunk, which are familiar to people. Therefore, as describedabove, a behavior of the object, such as turning, that reduces thepossibility of contact with the mobile apparatus can be induced, and thepossibility of contact between the mobile apparatus and the object canbe reduced.

According to a fifteenth aspect of the present invention, in the mobileapparatus according to the fourteenth aspect of the present invention,the mobile apparatus has a head as the movable part, and the thirdprocessing section sets an operation of turning the front of the headtoward the movement direction of the mobile apparatus as the secondaction plan element.

According to the fifteenth aspect of the present invention, the personrecognized as the object can naturally and clearly recognize themovement direction of the mobile apparatus from a familiar action ofturning the front of the head to the movement direction. Therefore, asdescribed above, a behavior of the object, such as turning, that reducesthe possibility of contact with the mobile apparatus can be induced, andthe possibility of contact between the mobile apparatus and the objectcan be reduced.

According to a sixteenth aspect of the present invention, there isprovided a method of controlling a mobile apparatus that autonomouslymoves according to a first action plan element, comprising: a step ofperforming first processing of recognizing a current image of the mobileapparatus, a current image of an object, and an intermittent orcontinuous future image of the object, which is determined according tothe behavior of the object and has a larger size than the current imagethereof, as a reference spatial element, a first spatial element and asecond spatial element having a larger size than the first spatialelement on a discriminant plane, respectively; a step of performingsecond processing of determining, based on a result of the recognitionin the first processing, whether or not there is a first spatial elementthat satisfies a contact condition that there is a possibility ofcontact with the reference spatial element on the discriminant plane;and a step of performing third processing of setting a route that allowsthe reference spatial element to avoid contact with the second spatialelement on the discriminant plane as the first action plan element basedon the result of the recognition by the first processing section, whenit is determined in the second processing that there is a first spatialelement that satisfies the contact condition on the discriminant plane.

According to the sixteenth aspect of the present invention, the mobileapparatus can move by avoiding contact with the object while reducingthe possibility of inducing a change of the behavior of the object, suchas a person.

According to a seventeenth aspect of the present invention, there isprovided a control program that makes a computer installed in the mobileapparatus according to the first aspect of the present inventionfunction as the control system.

According to the seventeenth aspect of the present invention, thecomputer installed in the mobile apparatus can be made to function as asystem for controlling the mobile apparatus so that the mobile apparatusmoves by avoiding contact with an object, such as a person, whilereducing the possibility of inducing a change of the behavior of theobject.

According to an eighteenth aspect of the present invention, there isprovided a supervisory system that distributes or broadcasts at least apart of the program according to the seventeenth aspect of the presentinvention to the computer installed in the mobile apparatus.

According to the eighteenth aspect of the present invention, a mobileapparatus capable of moving by avoiding contact with an object, such asa person, while reducing the possibility of inducing a change of thebehavior of the object can be provided at any point in time bydistributing a program to a computer installed in the mobile apparatus,for example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a configuration of a mobile apparatusaccording to the present invention;

FIG. 2 is a diagram for illustrating functions of the mobile apparatusaccording to the present invention;

FIG. 3 is a diagram for illustrating functions of the mobile apparatusaccording to the present invention;

FIGS. 4 a-4 b are diagrams for illustrating functions of the mobileapparatus according to the present invention;

FIGS. 5 a-5 c are diagrams for illustrating functions of the mobileapparatus according to the present invention;

FIG. 6 is a diagram for illustrating functions of the mobile apparatusaccording to the present invention;

FIG. 7 is a diagram for illustrating functions of the mobile apparatusaccording to the present invention;

FIG. 8 is a diagram for illustrating functions of the mobile apparatusaccording to the present invention; and

FIG. 9 is a diagram for illustrating functions of the mobile apparatusaccording to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A mobile apparatus or the like according to an embodiment of the presentinvention will be described with reference to the drawings.

First, a configuration of a robot, which is an embodiment of the presentinvention, will be described with reference to FIG. 1.

A robot 1 comprises a base body (trunk) 10, a head 11 disposed on top ofthe base body 10, left and right arms 12 extending from upper parts ofthe left and right sides of the base body 10, and left and right legs 13extending downwardly from the bottom of the base body 10. Suffixes “L”and “R” indicate left and right, respectively. As disclosed in thedomestic re-publications of PCT international publication for patentapplication Nos. 03/090978 and 03/090979, the robot 1 can bend the arms12 and the legs 13 by force transmitted from an unillustrated actuatorat a plurality of joint parts corresponding to a plurality of humanjoints including the shoulder joint, the elbow joint, the wrist joint,the hip joint, the knee joint and the ankle joint. The robot 1 canautonomously move by the movement of the left and right legs 13involving lifting off and landing on the floor. The height of the head11 can be adjusted by adjusting the angle of inclination of the basebody 10 with respect to the vertical direction. The head 11 incorporatesa pair of left and right CCD cameras 21 facing forward of the robot 1.The image pickup range of the CCD cameras 21 can be adjusted byrotation, inclination, or the like of the head 11 with respect to thebase body 10 by means of an actuator.

The robot 1 further comprises a control system 100 for controlling thewalking or running operation thereof. The control system 100 comprisesan ECU or a computer (composed of a CPU, a ROM, a RAM and an I/O, forexample) as hardware and a “control program” according to the presentinvention as software. The control program may be previously stored in amemory of the computer, or distributed or broadcasted from a server in a“supervisory system” according to the present invention to the computervia a network or an artificial satellite in response to a request fromthe robot 1 to the server and stored in the memory of the computer.

The control system 100 comprises a first processing section 110, asecond processing section 120, and a third processing section 130.

The first processing section 110 recognizes the robot 1 and the positionand the velocity thereof (the term “velocity” means the velocity vectordefined by direction and length hereinafter) as a reference spatialelement Q₀, a reference position O and a reference velocity v₀ on adiscriminant plane, respectively. Furthermore, the first processingsection 110 recognizes an object, such as a person, and the position andthe velocity thereof as a first spatial element Q₁, an object position pand an object velocity v on the discriminant plane, respectively.Furthermore, the first processing section 110 recognizes, as a secondspatial element Q₂, the first spatial element Q₁ intermittently orcontinuously extended based on the relative position of the objectposition p with respect to the reference position O and the relativevelocity of the object velocity v with respect to the reference velocityv₀. The shape and the size of the reference spatial element Q₀ on thediscriminant plane are read from a memory (not shown) and recognized.

Based on the result of recognition by the first processing section 110,the second processing section 120 determines whether or not there is afirst spatial element Q₁ that satisfies a “contact condition” that thereis a possibility of contact with the reference spatial element Q₀ on thediscriminant plane.

If the second processing section 120 determines that there is a firstspatial element Q₁ that satisfies the contact condition on thediscriminant plane, the third processing section 130 determines a routethat allows the reference spatial element Q₀ to avoid contact with thesecond spatial element Q₂ on the discriminant plane, which is referredto as “first action plan element”, based on the result of recognition bythe first processing section 110.

Now, functions of the robot configured as described above will bedescribed with reference to FIGS. 2 to 9.

For example, the robot 1 is walking or running along a route R_(k) asthe first action plan element, which is set previously or set by thethird processing section 130 as described later, as shown by thealternate long and short dash line in FIG. 6.

The first processing section 110 performs a “first processing” (S110 inFIG. 2).

The first processing section 110 recognizes the robot 1 and the positionand the velocity thereof as the reference spatial element Q₀ on thediscriminant plane, and the reference position O and the referencevelocity v₀ in a robot coordinate system, respectively (S112 in FIG. 2).For example, as shown in FIG. 6, the robot 1 and the position and thevelocity thereof are recognized as dots or small regions on thediscriminant plane that represent the reference spatial element Q₀, thereference position O and the reference velocity v₀. As described later,the position of an object x measured based on an image obtained by theCCD cameras 21 is the relative position with respect to the robot 1, andtherefore, the measurement of the position of the robot 1 is omitted.However, if the measured position of the object x is not the relativeposition, for example, if the measured position of the object x isrepresented by the latitude and longitude thereof, the position of therobot 1 is measured to measure the relative position. The position ofthe robot 1 is determined based on signals indicating the latitude andlongitude thereof, which are provided by a GPS function thereof, orsignals indicating the acceleration of the robot 1, which aresuccessively output from a gyroscope. The velocity of the robot 1 can bedetermined based on a time series of measured positions of the robot 1,signals output from the gyroscope, or the angles of the joints of thelegs 13 and an inverse dynamics model, for example.

In addition, the first processing section 110 recognizes an object, suchas a person, and the position and the velocity thereof as the firstspatial element Q₁, the object position p and the object velocity v onthe discriminant plane, respectively (S114 in FIG. 2). For example, asshown in FIG. 3, if there are objects x₁ to x₄ ahead of the robot 1 (inthe image pickup range of the CCD cameras 21), the objects x₁ to x₄ andthe positions and the velocity vectors thereof are recognized as firstspatial elements (regions) Q₁₁ to Q₁₄, the object positions p₁ to p₄ andthe object velocities v₁ to v₄ on the discriminant plane, respectively,as shown in FIG. 6. The position of the object x is determined byanalysis of an image of the object x obtained by the CCD cameras 21. Theposition determined based on the image obtained by the CCD cameras 21 isthe relative position with respect to the robot 1.

The shape and the size of the reference spatial element Q₀ on thediscriminant plane can be read from a memory (which stores the shape andthe size of the robot 1) and recognized. Furthermore, the shape and thesize of the first spatial element Q₁ on the discriminant plane can berecognized by recognizing the type (a human being, a dog (a smallanimal) or the like) of the object x based on the image obtained by theCCD cameras 21 and then inquiring of the memory or database (whichstores or manages the types, the shapes and the sizes of objectsassociated with each other) about the result of the recognition. Theshape and the size of the first spatial element Q₁ on the discriminantplane may be recognized by performing an arithmetic operation on theimage data obtained by an image pickup device, such as the CCD cameras21, according to an algorithm or the like that converts the(two-dimensional) image into a (three-dimensional) real space.Furthermore, the position of the object x may be measured or recognizedbased on a signal indicating the latitude and longitude thereof receivedfrom a communication device or the like on the object x. Furthermore,the velocity of the object x may be measured as a time variation of theposition of the object x. While the discriminant plane can be defined asa flat surface or curved surface in which any point can be specified bythe latitude and longitude thereof, the discriminant plane may beappropriately defined based on the angle of inclination of the flooraround the robot 1 or the condition of the floor, such as the presenceor absence of steps or irregularities, which are recognized based on theimage obtained by the CCD cameras 21.

In the case where another object, such as a box and a device, movesintegrally with the robot 1, for example, in the case where the robot 1holds a box with the arms 12, or in the case where an optional devicefor adding a function to the robot 1 is attached to the base body 10,the composite shape and the composite size of the robot 1 and the objectmoving integrally can be recognized as the shape and the size of therobot 1.

A region determined according to the contour characteristics (shape andsize) of the object x on the discriminant plane that is extendedaccording to the contour characteristics of the robot 1 is recognized asthe first spatial element Q₁. More specifically, a Minkowski sum of tworegions on the discriminant plate that have contour characteristicsdetermined according to the contour characteristics of the robot 1 andthe object x is recognized as the first spatial element Q₁. For example,in the case where the robot 1 and the object x are defined on thediscriminant plane as a circular robot region q_(robot) and arectangular object region q_(object) as shown in FIG. 4( a),respectively, a Minkowski sum of the two regions (q_(robot)+q_(object)),which is represented by a rounded rectangular region as shown in FIG. 4(b), is recognized as the first spatial element Q₁. Supposing that therobot region q_(robot) moves around the object region q_(object) in sucha manner that the center of the robot region q_(robot) follows thecontour of the object region q_(object), the Minkowski sum is equivalentto the sum of the object region q_(object) and the annular regiondefined by the trajectory of the robot region q_(robot) outside theobject region q_(object). The shape and the size of the robot regionq_(robot), which are associated with the size (or the shape and thesize) of the robot 1, are previously stored in the memory and read fromthe memory and recognized. The object region q_(object) is recognized asa region having a size determined by the size (or the shape and thesize) of the object x recognized based on the image obtained by the CCDcameras 21. Alternatively, the object region q_(object) may be directlyrecognized as the first spatial element Q₁, or an object regionq_(object) extended according to the contour characteristics, such assize, of the robot region q_(robot), other than the Minkowski sum, maybe recognized as the first spatial element Q₁.

Furthermore, the first processing section 110 recognizes the firstspatial element Q₁ extended according to the reference position O, theobject position p, the reference velocity v₀ and the object velocity vas the second spatial element Q₂ (S116 in FIG. 2). For example, as aresult of the first spatial element Q₁ shown in the left part of FIG. 5(a) being continuously extended in the direction of the relative velocity(vector) v−v₀ of the object velocity v with respect to the referencevelocity v₀, the second spatial element Q₂ having the shape of asubstantially straight band shown in the right part of FIG. 5( a) isrecognized. The amount of extension of the first spatial element Q₁ isdetermined by the velocity v of the first spatial element, the objectposition (relative position) p (=p−O), and the relative velocity v−v₀according to the following formula (1).(amount of extension)=|p|·|v|/|v−v ₀|  (1)

Similarly, as a result of the first spatial element Q₁ shown in the leftpart of FIG. 5( b) being continuously extended so that the first spatialelement Q₁ slews in the direction of the relative velocity v−v₀, thesecond spatial element Q₂ having the shape of a bent band shown in theright part of FIG. 5( b) is recognized. In the situation shown in FIG. 3described above, second spatial elements Q₂₁ to Q₂₄ shown in FIG. 6 arerecognized. Alternatively, as a result of the first spatial element Q₁shown in the left part of FIG. 5( c) being intermittently extended inthe direction of the relative velocity v−v₀, the second spatial elementQ₂ composed of separate spatial elements shown in the right part of FIG.5( c) may be recognized. The extension part of the first spatial elementQ₁ corresponds to a future image of the object predicted based on thebehavior (position and velocity) of the object.

Then, the second processing section 120 performs a “second processing”to determine whether or not there is a possibility of contact betweenthe reference spatial element Q₀ and the first spatial element Q₁ on thediscriminant plane recognized by the first processing section 110, thatis, whether or not there is a possibility of contact between the robot 1and each object (S120 in FIG. 2).

The second processing section 120 determines whether or not there is afirst spatial element Q₁ that satisfies a “first contact condition”concerning the movement cost of the reference spatial element Q₀ on thediscriminant plane (S122 in FIG. 2).

The movement cost is evaluated by the third processing section 130 as afunction of either or both of the time required for the referencespatial element to come into contact with the first spatial element onthe discriminant plane and the distance the reference spatial elementmoves until the reference spatial element comes into contact with thefirst spatial element on the discriminant plane. As the movement cost,the direct distance or distance d along the route (shown by thealternate long and short dash line) from the reference spatial elementQ₀ to each of the first spatial elements Q₁₁ to Q₁₄ shown in FIG. 6, thetime t (=(d/|v₀−v|)) required for the reference spatial element Q₀ andeach of the first spatial elements Q₁₁ to Q₁₄ moving at the referencevelocity v₀ and the velocity v, respectively, to come into contact witheach other, or the increasing function of either or both of the distanced and the required time t is evaluated.

For example, consider a case where a first contact condition that themovement cost falls within a prescribed range {0, ε₊(>0)} is used, andthe route R_(K) shown by the alternate long and short dash line in FIG.6 is set according to the latest action plan. In this case, it can bedetermined that, of the four first spatial elements Q₁₁ to Q₁₄, threefirst spatial elements Q₁₁ to Q₁₃ closer to the reference spatialelement Q₀ satisfy the first contact condition.

If the second processing section 120 determines that there is a firstspatial element Q₁ that satisfies the first contact condition (YES inS122 in FIG. 2), the second processing section 120 determines whether ornot there is a first spatial element Q₁ that satisfies a “second contactcondition” concerning the positional relationship between the firstspatial element Q₁ and the route R_(K) of the reference spatial elementQ₀ from the reference position O to a target position p_(d) on thediscriminant plane set according to the action plan of the robot 1 (S124in FIG. 2).

For example, consider a case where a second contact condition that thereis an intersection or contact between the route R_(K) and the firstspatial element Q₁ is used, and the route R_(K) shown by the alternatelong and short dash line in FIG. 6 is set as a first action planelement. In this case, it is determined that, of the three first spatialelements Q₁₁ to Q₁₃ that satisfy the first contact condition describedabove, the first spatial element Q₁₂ that intersects with the routeR_(K) satisfies the second contact condition. The second contactcondition may be that the shortest distance to the first spatial elementQ₁ or a cumulative distance or an integral along a part or the whole ofthe route R_(K) is equal to or smaller than a predetermined value, orthat there is an intersection or contact between the first spatialelement Q₁ and the tangent to the route R_(K) at the reference positionO (which extends in the direction of movement of the reference spatialelement Q₀).

If there is a first spatial element Q₁ that satisfies both the firstcontact condition and the second contact condition as described above(if YES in S122 and S124 in FIG. 2), it is determined that there is afirst spatial element Q₁ that can come into contact with the referencespatial element Q₀. Alternatively, it can also be determined that thereis a first spatial element Q₁ that can come into contact with thereference spatial element Q₀, even if the first spatial element Q₁satisfies only one of the first contact condition and the second contactcondition.

If the second processing section 120 determines that there is a firstspatial element Q₁ that satisfies the second contact condition (YES inS124 in FIG. 2), the third processing section 130 performs a “thirdprocessing” to set a new route for the reference spatial element Q₀ thatallows the reference spatial element Q₀ to avoid contact with all thesecond spatial elements Q₂ as the first action plan element (S130 inFIG. 2).

As described above, in the example shown in FIG. 6, since one firstspatial element Q₁₂ of the four first spatial elements Q₁₁ to Q₁₄satisfies the first and the second contact condition, a new routeR_(K+1) that allows the reference spatial element Q₀ to avoid contactwith all the second spatial elements Q₂₁ to Q₂₄ shown by the solid lineis set as the first action plan element. In response to this, the robot1 moves along the route R_(K+1) as a new first action plan element shownby the solid line in FIG. 6 rather than the route R_(K) as the previousfirst action plan element shown by the alternate long and short dashline in FIG. 6.

Furthermore, the third processing section 130 determines whether or notthe distance |O−p_(d)| between the reference position O and the targetposition p_(d) of the reference spatial element Q₀ on the discriminantplane is equal to or less than a threshold value δ, or in other words,whether or not the robot 1 has reached the target position (S132 in FIG.2). Even if the result of the determination by the second processingsection 120 is negative (if NO in S122 and S124 in FIG. 2), thedetermination (S132 in FIG. 2) is made.

If the result of the determination is negative (if NO in S132 in FIG.2), the first processing, the second processing and the like describedabove are performed again. For example, in the case where the situationshown in FIG. 6 changes to the situation shown in FIG. 7, and it isdetermined that one first spatial element Q₁₂ of the four first spatialelements Q₁₁ to Q₁₄ satisfies both the first and the second contactcondition again, the route R_(K+1) shown by the alternate long and shortdash line as the previous first action plan element in FIG. 7 is changedto a new route R_(K+2) shown by the solid line as a new first actionplan element. On the other hand, the result of the determination ispositive (if YES in S132 in FIG. 2), the procedure described above isended.

The robot 1 capable of serving the functions described above is reducedin the frequency of change of the route R_(k) as the first action planelement for the reasons described below.

The determination of whether the second contact condition is satisfiedor not is made only for a first spatial element Q₁ that satisfies thefirst contact condition concerning the movement cost on the discriminantplane (see S122 (YES) and S124 in FIG. 2). Therefore, for a firstspatial element Q₁ corresponding to an object x located far from therobot 1, the determination of whether the second contact condition issatisfied or not, and therefore, the determination of whether a routechange is needed or not are not made. As a result, the frequency ofchange of the route R_(k) is reduced compared with the case where thedetermination of whether the second contact condition is satisfied ornot is made for all the first spatial elements Q₁.

In addition, it is a requirement for changing the route R_(k) that atleast one of the first spatial elements Q₁ that satisfy the firstcontact condition on the discriminant plane satisfies the second contactcondition concerning the positional relationship between the firstspatial element Q₁ and the current route (see S124 (YES) and S130 inFIG. 2). The first spatial element Q₁ is recognized as a relativelysmall spatial element on the discriminant plane (see FIGS. 5( a) to5(c)). Therefore, the frequency of change of the route R_(k) as thefirst action plan element is reduced compared with the case where thedetermination of whether the second contact condition is satisfied ornot is made for a spatial element larger than the first spatial elementQ₁, such as the second spatial element Q₂.

Furthermore, the shape and the size of the first spatial element Q₁ onthe discriminant plane can be recognized by inquiry of the database orthe like. Therefore, an object x can be prevented from being recognizedas a first spatial element Q₁ having a size larger than the actual sizeof the object x on the discriminant plane because of the limit of theprecision of measurement of the size (or the shape and the size) of theobject x by the CCD cameras 21 or the like. As a result, the frequencyof change of the route as the first action plan element, andaccordingly, the frequency of change of the movement direction or thelike of the robot 1 are reduced. In other words, frequent changes of theroute of the robot 1 due to the limit of the recognition of the contourcharacteristics of the object x by the CCD cameras 21 or the like can beavoided.

The frequency of change of the route R_(k) as the first action planelement is reduced as described above, and accordingly, the frequency ofchange of the behavior of the robot 1, such as change of the movementdirection of the robot 1, is reduced. As a result, it is possible toprevent a change of the behavior of the robot 1 from inducing a changeof the behavior of the object x, such as a person, and increasing thepossibility of contact between the robot 1 and the object x.Furthermore, since the frequency of change of the route R_(k) as thefirst action plan element is reduced, the information processing loadinvolved with the route change can be reduced accordingly.

For the reasons described below, an appropriate route R_(k+1) is set toavoid the contact between the robot 1 and the object x with reliability.As described above, in the case where there is at least one firstspatial element Q₁ that satisfies both the first contact condition andthe second contact condition on the discriminant plane, a new routeR_(k+1) that allows the reference spatial element Q₀ to avoid contactwith the second spatial element Q₂ is set (see S122 (YES), S124 (YES)and S130 in FIG. 2, and FIGS. 6 and 7). The second spatial element Q₂ isrecognized as a relatively large spatial element on the discriminantplane (see FIGS. 5( a) to 5(c)). Therefore, an appropriate route R_(k+1)for avoiding contact between the robot 1 and the object x withreliability is set compared with the case where a new route for thereference spatial element Q₀ is set with respect to a spatial elementsmaller than the second spatial element Q₂, such as the first spatialelement Q₁.

Furthermore, the shape and the size of the first spatial element Q₁ onthe discriminant plane are recognized by inquiry of the database or thelike, and the shape and the size of the second spatial element Q₂ aredetermined based on the shape and the size of the first spatial elementQ₁. Therefore, the object x can be prevented from being recognized as asecond spatial element Q₂ having a size larger than the actual sizethereof on the discriminant plane because of the limit of the precisionof measurement of the size of the object x by the CCD cameras 21 or thelike. In addition, the route as the first action plan is prevented frombeing excessively frequently changed in order to avoid contact with theobject x.

Now, there will be described an embodiment in which each of the spatialelements Q₀, Q₁ and Q₂ is recognized on each of a plurality ofdiscriminant planes, rather than on one discriminant plane, and it isnecessary for changing the first action plane element that there is afirst spatial element Q₁ that satisfies the first and the second contactcondition in any of the plurality of discriminant planes.

For example, there will be discussed a situation shown in FIG. 8 inwhich the robot 1 passes by a first object x₁ shorter than the robot 1,such as a cat and a dog, and a second object x₂ substantially as tall asthe robot 1, such as a human being.

In this situation, if the robot 1, the first object x₁ and the secondobject x₂ are recognized on only one discriminant plane P, the referencespatial element Q₀ and the first spatial elements Q₁₁ and Q₁₂ shown inFIG. 9( c) can be recognized on the discriminant plane P. In this case,it can be determined that there is a first spatial element Q₁ thatsatisfies the first and the second contact condition, and the routeR_(k) can be changed to a new route R_(k+1) (see S124 (YES) and S130 inFIG. 2). That is, since the three-dimensional contour characteristics ofthe robot 1 and the like are not taken into account, the first spatialelement Q₁ is recognized as a large spatial element, and accordingly,the possibility that a new first action plan element is set to avoidcontact between the robot 1 and the object x increases.

On the other hand, since the reference spatial element Q₀ or the like isrecognized on each of the plurality of discriminant planes, the routecan be changed at an appropriate frequency in view of thethree-dimensional contour characteristics of the robot 1 and each objectx, and an appropriate route can be set to avoid contact between therobot 1 and each object x with reliability.

For example, consider a case where the reference spatial element Q₀ orthe like is recognized on each of a discriminant plane P(h₁) at a heightof h₁ and a discriminant plane P(h₂) at a height of h₂ (>h₁) from afloor face in the situation described above. In this case, on thediscriminant plane P(h₁), the first object x₁ and the second object x₂are recognized as the first spatial elements Q₁₁ and Q₁₂, respectively,as shown in FIG. 9( a). On the discriminant plane P(h₂) at the height ofh₂ (>h₁), only the second object x₂ is recognized as the first spatialelements Q₁₂ as shown in FIG. 9( b).

On the discriminant plane P(h₂), the first object x₁ is not recognized.This is because the height of the first object x₁ is lower than theheight h₂.

In addition, the second object x₂ is recognized as a relatively largefirst spatial element Q₁₂ on the discriminant plane P(h₂), while thesecond object x₂ is recognized as a relatively small first spatialelement Q₁₂ on the discriminant plane P(h₁). This is because the upperbody of the robot 1 is larger than the lower body because of thepresence of the arms 12 and the like (see FIG. 1), and the upper body ofa human being, which is the second object x₂, is also larger than thelower body. In other words, the Minkowski sum of the robot regionq_(robot) and the object region q_(object) on the discriminant planeP(h₂), which includes the upper body of the robot 1 and the secondobject x₂, is larger than the Minkowski sum (q_(robot)+q_(object)) ofthe robot region q_(robot) and the object region q_(object) on thediscriminant plane P(h₁), which includes the lower body of the robot 1and the second object x₂ (see FIG. 4). It is determined that there is nofirst spatial element Q₁ that satisfies the second contact conditionbecause no first spatial element Q₁ intersect with the route R_(k)extending from the reference spatial element Q₀ to the target positionp_(d) on both the two discriminant planes P(h₁) and P(h₂), and the routeR_(k) as the first action plan element is not changed (see S124 (NO) inFIG. 2).

Thus, the route R_(k) can be changed at an appropriate frequency in viewof the three-dimensional shape and the size of the robot 1 and theobjects x. In general, the robot 1 and the objects x each have contourcharacteristics that the shape and the size vary with the positionthereof, such as the height from the floor surface. Therefore, the shapeand the size of the robot 1 and the objects x at different positions(heights) can be reflected in the shape and the size of the firstspatial element Q₁ recognized on each of the plurality of discriminantplanes. Thus, a route R_(k) as the first action plan element can bechanged at an appropriate frequency to avoid contact between the robot 1recognized as the reference spatial element Q₀ and the object xrecognized as the first spatial element Q₁ in view of thethree-dimensional contour characteristics and the behavior, such as theposition and the velocity, of the robot 1 and the object x.

Furthermore, a route R_(k+1) that allows the reference spatial elementQ₀ to avoid contact with the second spatial element Q₂ on all of theplurality of discriminant planes is set as the first action planelement. Therefore, an appropriate route R_(k+1) for avoiding contactbetween the robot 1 and the object can be set in view of thethree-dimensional shape and the size of the robot 1 and the object.

Therefore, the robot 1 can continue moving by avoiding contact with anobject x, such as a person, while reducing the possibility that themovement of the robot 1 induces a change of the behavior of the objectx.

Furthermore, the Minkowski sum (q₀+q) of the two regions q₀ and qdetermined according to the contour characteristics of the robot 1 andthe object x is recognized as the first spatial element Q₁. Therefore,the size and the shape of the robot 1 and the object x can becollectively reflected in the size and the shape of the first spatialelement Q₁ on each discriminant plane. Thus, the precision of thedetermination of whether there is a first spatial element Q₁ that cancome into contact with the reference spatial element Q₀ or not can beimproved or maintained while simplifying the handling of the referencespatial element Q₀ on the discriminant plane as a dot or a small regionand therefore the determination process, for example.

The control method described above can be applied not only to the robotthat moves by the movement of a pair of left and right legs, such as therobot 1, but also to any mobile apparatus, such as a robot that moves bythe movement of three or more legs and a wheeled mobile robot(automobile).

If the lower limit of the prescribed range of the movement cost is setat a positive value rather than 0, when the movement cost is lower thanthe lower limit, the first contact condition is not satisfied, and theroute R_(k) as a new first action plan element is not changed (see S122(NO) in FIG. 2). Therefore, when the object x is located near the robot1, and therefore, a change of the behavior of the robot 1 can induce achange of the behavior of the object x to thereby increase thepossibility of contact between the robot 1 and the object x, themovement direction of the robot 1 is not changed.

Furthermore, a condition that the rate of change of either or both ofthe direction and the magnitude of the velocity of the reference spatialelement Q₀, that is, the robot 1, is equal to or lower than a thresholdvalue can be set as a (additional) first action plan element. In thiscase, an excessive change of the velocity of the robot 1 caused by achange of the first action plan element and a change of the behavior ofthe robot 1 caused thereby can be suppressed. In addition, thepossibility can be avoided that the behavior of the robot 1 induces anunexpected change of the behavior of the object x to thereby increasethe possibility of contact between the robot 1 and the object x.Furthermore, the possibility can be avoided that the robot 1 is forcedto change the velocity and, therefore, the behavior beyond the capacitythereof.

Furthermore, the first action plan element can also be set in such amanner that a higher priority is given to changing the magnitude of thevelocity of the reference spatial element Q₀, that is, the robot 1 thanchanging the direction thereof. In this case, a higher priority is givento changing the magnitude of the velocity (speed) of the robot 1 thanchanging the direction thereof because a change of the direction of thevelocity (movement direction) of the robot 1 is more likely to induce achange of the behavior of the object. Thus, the possibility that achange of the behavior of the robot 1 induces a change of the behaviorof the object x is reduced.

Furthermore, the third processing section 130 can prepare anannouncement of the movement direction of the robot 1 as a “secondaction plan element”, and the control system 100 can control theoperation of the equipment on the robot 1 according to the second actionplan. For example, the operation of actuators installed in the robot 1can be controlled to previously announce the movement direction of therobot 1 in the form of the movement of the movable parts correspondingto parts of a human body, such as the base body 10, the head 11, thearms 12 and the legs 13, according to the second action plan element. Inthis case, the person (object x) can naturally clearly recognize themovement direction of the robot 1 without giving a feeling of physicaldisorder to the person (object x) from a familiar action, such aschanging the direction of the front (face) of the head 11, changing theposture of the arms 12, and twisting the upper part of the base body 10with respect to the lower part. As a result, the possibility can bereduced that a movement of the robot 1 induces a movement of the objectx, such as a change of the movement direction, to thereby cause contactbetween the robot 1 and the object x. Alternatively, the robot 1 can beequipped with a direction indicator, a light emitting device, a soundoutputting device or the like, and the operation of the directionindicator, the light emission of the light emitting device or the soundoutput of the sound outputting device can be controlled according to thesecond action plan element to announce the movement direction of therobot 1.

1. A mobile apparatus that has a control system and autonomously movesaccording to a first action plan element configured to define a behaviorof a positional change of the mobile apparatus under the control of thecontrol system, wherein said control system comprises: a firstprocessing section that recognizes a current image of said mobileapparatus, a current image of an autonomously movable object, and anintermittent or continuous future image of the object, which isdetermined according to a behavior of the object and has a larger sizethan the current image thereof, as a reference spatial element, a firstspatial element, and a second spatial element having a larger size thanthe first spatial element on a discriminant plane which is a flatsurface or a curved surface defined to two-dimensionally recognize aposition, a shape and a size of the mobile apparatus in a real spacethereof and a position, a shape and a size of the object in a real spacethereof, respectively; a second processing section that determines,based on the result of the recognition by the first processing section,whether or not there is a first spatial element that satisfies both afirst contact condition that a movement cost which is defined toincrease is a distance from the reference spatial element to the firstspatial element on the discriminant plane increases is in a prescribedrange or not higher than a predetermined rank and a second contactcondition that there is an intersection or contact on the discriminantplane between the first spatial element and the reference spatialelement moving along a route serving as the first action plan element,or the second contact condition only; and a third processing sectionthat sets a next route that allows the reference spatial element toavoid contact with the second spatial element on the discriminant planeas said first action plan element based on the result of the recognitionby the first processing section on a condition that the secondprocessing section determines that the first spatial element thatsatisfies both the first contact condition and the second contactcondition, or the second contact condition only is present on thediscriminant plane.
 2. The mobile apparatus according to claim 1,wherein said first processing section recognizes the behavior of saidobject by some or all of a position, a velocity and an acceleration ofsaid first spatial element on said discriminant plane and recognizes thefirst spatial element intermittently or continuously extended accordingto the result of the recognition as the second spatial element.
 3. Themobile apparatus according to claim 2, wherein said first processingsection recognizes the behavior of said object by the velocity of saidfirst spatial element and the relative position and the relativevelocity of said first spatial element with respect to said referencespatial element on said discriminant plane and recognizes the firstspatial element intermittently or continuously extended according to theresult of the recognition as said second spatial element.
 4. The mobileapparatus according to claim 1, wherein said first processing sectionrecognizes a region determined according to contour characteristics ofsaid object extended according to contour characteristics of said mobileapparatus as said first spatial element on said discriminant plane. 5.The mobile apparatus according to claim 4, wherein said first processingsection recognizes a Minkowski sum of two regions determined accordingto the contour characteristics of said mobile apparatus and said objectas said first spatial element on the discriminant plane.
 6. The mobileapparatus according to claim 1, wherein said second processing sectiondetermines whether or not there is the first spatial element thatsatisfies the first contact condition that the movement cost is in theprescribed range having a positive lower limit.
 7. The mobile apparatusaccording to claim 1, wherein said third processing section sets, assaid first action plan element, a condition that the rate of change ofeither or both of the direction and the magnitude of a velocity of saidmobile apparatus is equal to or lower than a threshold value.
 8. Themobile apparatus according to claim 1, wherein said third processingsection sets, as said first action plan element, a condition that ahigher priority is given to changing the magnitude of a velocity of saidmobile apparatus than changing the direction thereof.
 9. The mobileapparatus according to claim 1, wherein said control system controlsoperation of an on-board device installed in said mobile apparatusaccording to a second action plan element configured to define abehavior of the operation of the on-board device, and said thirdprocessing section sets the actuation of the on-board device as thesecond action plan element so as to prepare an announcement of a movingdirection of the mobile apparatus.
 10. The mobile apparatus according toclaim 9, wherein the mobile apparatus has a driving device for actuatinga movable part corresponding to a part of a human body as said on-boarddevice, and said third processing section sets the actuation of theon-board device as the second action plan element so as to prepare anannouncement of a moving direction according to a motion of the movablepart actuated by the driving device.
 11. The mobile apparatus accordingto claim 9, wherein said mobile apparatus has a head as said movablepart, and said third processing section sets an operation of turning afront of the head toward the movement direction of said mobile apparatusas said second action plan element.
 12. A control system of a mobileapparatus that autonomously moves according to a first action planelement configured to define a behavior of a positional change of themobile apparatus, comprising: a first processing section that recognizesa current image of said mobile apparatus, a current image of anautonomously movable object, and an intermittent or continuous futureimage of the object, which is determined according to a behavior of theobjet and has a larger size than the current image thereof, as areference spatial element, a first spatial element, and a second spatialelement having a larger size than the first spatial element on adiscriminant plane which is a flat surface or a curved surface definedto two-dimensionally recognize a position, a shape and a size of themobile apparatus in a real space thereof and a position, a shape and asize of the object in a real space thereof, respectively; a secondprocessing section that determines, based on the result of therecognition by the first processing section, whether or not there is afirst spatial element that satisfies both a first contact condition thata movement cost which is defined to increase as a distance from thereference spatial element to the first spatial element on thediscriminant plane increases is in a prescribed range or not higher thana predetermined rank and a second contact condition that there is anintersection or contact on the discriminant plane between the firstspatial element and the reference spatial element moving along a routeserving as the first action plan element, or the second contactcondition only; and a third processing section that sets a next routethat allows the reference spatial element to avoid contact with thesecond spatial element on the discriminant plane as said first actionplan element based on the result of the recognition by the firstprocessing section on a condition that the second processing sectiondetermines that the first spatial element that satisfies both the firstcontact condition and the second contact condition, or the secondcontact condition only is present on the discriminant plane.
 13. Thecontrol system according to claim 12, wherein a program makes a computerinstalled in the mobile apparatus function as said control system. 14.The control system according to claim 12, wherein a supervisory system,which supervises a mobile apparatus that autonomously moves according toa first action plan element configured to define a behavior of apositional change of the mobile apparatus, distributes or broadcasts atleast a part of the program to said computer installed in said mobileapparatus.